The mechanical buttocks may look like
a new low for the world of Japanese robotics, but they are one of the
first robots that can convey emotions.

The emotions in question are simple - fear, joy and relaxation.

Spank the buttocks, and they quiver.
Stroke them and they clench, using artificial muscles under their
silicone skin. A built-in microphone detects slaps.

‘I wanted to try and use a butt to
reflect emotions - fear, joy and relaxation,’ said the 24-year-old Nobuhiro Takahashi,
a graduate student at the Tokyo University of Electro-Communication.

The inventor hopes to apply his ideas to robot faces in the future.

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Emotional behind: Japanese scientists have created a robotic bottom that can 'display emotion' by, for instance, clenching when stroked

Up close and personal: The ro-butt is called 'Shiri', and 'represents emotions with visual and tactual transformation of the muscles'

Inventor Nobuhiro Takahashi programmed
his creation, called ‘SHIRI’ or ‘butt’ in Japanese, to respond with
different emotions to different human touches.

Takahashi hopes to use the proto-type
technology to develop responses which can be applied to other part of a
robot's body, in particular the face, to help with non-verbal
communication.

He decided to develop his technology
with a rear end because a bottom's movements are large and make it
easier to convey emotion.

Robots are able to communicate with
voices but have largely lacked the sort of non-verbal, physical
responses that help power much of human communication. Takahashi hopes
his technology can

‘Fear is a very human - very living -
emotion, so it's expressed with force, with a spank,’ he said, speaking
inside a black tent designed to keep light from damaging the
silicon-coated invention.

The robot bottom responds to a hit
with quivering. A slow wobble is its default state, the sign for
relaxation, while a gentle stroke brings clenches that Takahashi said
signal pleasure.

The 'robo-bot', or 'ro-butt' contains a
skin of silicone over a foam structure, under which lies 'a gluteus
maximum actuator', or artificial muscles that be inflated or deflated to
simulate different 'moods'.

Stimulation: The buttocks respond to gestures such as stroking or slapping

Uncanny valley: From the outside, the buttocks look realistic - but get under the skin and you can see the 'gluuteus maximum actuator'

Also tucked away inside is an internal
microphone, which detects when the cheeks are being touched, rubbed or
slapped ad responds accordingly.

Among its many moves are twitching, clenching or protruding, and the results in the video are indeed realistic.

Despite
the inherent creepiness of seeing disjointed buttocks responding to
human touches, the projects shows just how close we are getting to
realistic human-shaped robots, long a staple of science fiction.

Pneumatically activated muscles that can be inflated or deflated to simulate the many subtle moods of the rear